From tranquil ponds to laboratory beakers, science is uncovering the remarkable healing powers of Nymphaea pubescens.
When you picture a water lily, you might imagine a beautiful flower floating serenely on a pond, adding a touch of natural elegance to its surroundings. But beneath its striking pink blossoms and heart-shaped leaves lies a potent therapeutic powerhouse that has been used in traditional medicine for centuries. Recent scientific investigations are now validating what ancient healers long understood—that the hairy water lily (Nymphaea pubescens) possesses remarkable chemical properties with significant potential for modern medicine. This unassuming aquatic plant is emerging as a fascinating subject in the search for novel treatments for everything from infectious diseases to cardiovascular disorders.
Nymphaea pubescens, commonly known as the hairy water lily, pink water lily, or red water lily, is a perennial aquatic plant distinguished by its fuzzy leaf stalks and vibrant pink flowers that open at night and close during the day 3 . This macrophyte thrives in temperate and tropical shallow lakes and ponds across Asia, including India, Thailand, Sri Lanka, Bangladesh, and Malaysia 3 .
The plant holds significant cultural and economic value. It's cultivated for horticultural purposes, used as a temple offering, employed in traditional diabetic treatments, and its seeds have been utilized as a rice substitute and potential raw material for the food industry 3 .
In some regions like Sri Lanka and the United Kingdom, this species displays invasive characteristics that can cause serious water quality issues when it grows excessively 3 . Its invasiveness is largely attributed to its resilient rhizome system and seeds that have 100% germination rate, making population control challenging 1 .
Scientific analysis has revealed that Nymphaea pubescens is rich in various bioactive compounds that contribute to its medicinal properties. The plant contains multiple valuable phytochemicals, including flavonoids, alkaloids, phenolic acids, terpenoids, anthraquinones, saponins, and tannins 2 3 .
Different extraction methods yield different phytochemical profiles, as demonstrated in the following table comparing extracts from the leaves:
| Phytochemical | Aqueous Extract | Acetone Extract | Ethanol Extract |
|---|---|---|---|
| Flavonoids | |||
| Alkaloids | |||
| Phenolic acids | |||
| Terpenoids | |||
| Anthraquinones | |||
| Saponins | |||
| Tannins |
Note: denotes presence; denotes absence
High-performance liquid chromatography (HPLC) analysis has identified specific dominant compounds within these broad categories:
The flowers specifically have been found to contain a unique quercetin derivative called quercetin 3-methyl ether 3′-O-β-xylopyranoside, which has been identified as the main compound in ethanolic extracts of N. pubescens petals 5 8 .
This particular compound has demonstrated significant vasorelaxant and hypotensive effects, providing pharmacological evidence for the traditional use of this plant in treating conditions associated with endothelial dysfunction 5 .
One of the most promising areas of Nymphaea pubescens research involves its effects on the cardiovascular system. A groundbreaking 2024 study published in Frontiers in Pharmacology meticulously investigated the vasorelaxant and hypotensive effects of an ethanolic extract of N. pubescens petals and its main compound (quercetin 3-methyl ether 3′-O-β-xylopyranoside) 5 8 .
Petals of N. pubescens were collected, dried, ground into powder, and macerated with 95% ethanol. The crude ethanolic extract was then filtered and evaporated until dry, yielding 32.33% (w/w) of extract 5 .
The main compound (quercetin 3-methyl ether 3′-O-β-xylopyranoside, referred to as Compound 1) was isolated and purified using solid phase extraction and preparative PLC, with purity greater than 98% as measured by HPLC 5 .
The effects were tested on isolated mesenteric arteries from Wistar rats. The arterial rings were mounted in organ chambers, and their contractile responses were measured using a force transducer connected to a myograph system 5 .
The hypotensive effects were evaluated in anesthetized rats after intravenous infusion of either the vehicle, WL extract, or Compound 1 at various doses (0.01, 0.025, 0.05, 0.1, 0.5, and 1 mg/kg), with nifedipine used as a positive control 5 .
The findings provided compelling evidence for the traditional use of water lily in conditions like erectile dysfunction and cardiometabolic diseases:
Both the WL extract and Compound 1 induced significant vasorelaxation in the mesenteric arteries, with EC50 values of 0.08 ± 0.01 mg/mL and 42.8 ± 6.3 µM, respectively 5 . These relaxations were reduced by endothelium removal, indicating they depend partially on the inner lining of blood vessels.
The study demonstrated that the vasorelaxant effects rely on the potentiation of the NO-cGMP pathway (a key signaling mechanism that regulates blood vessel relaxation) and calcium inhibitory effects 5 .
| Parameter | WL Extract | Compound 1 |
|---|---|---|
| EC50 Value | 0.08 ± 0.01 mg/mL | 42.8 ± 6.3 µM |
| Reduced by endothelium removal? | Yes | Yes |
| Primary Mechanism | Potentiation of NO-cGMP pathway and calcium inhibition | Potentiation of NO-cGMP pathway and calcium inhibition |
| Hypotensive Effect | Significant reduction in systolic and diastolic blood pressure | Similar to nifedipine without rebound tachycardia |
Another promising application of Nymphaea pubescens lies in its antimicrobial capabilities. A 2023 study published in Plants investigated the in vitro antimicrobial activity of extracts from N. pubescens leaves against pathogenic bacteria commonly found in freshwater fish and brackish aquatic animals 2 .
The research compared aqueous, acetonic, and 95% ethanolic extracts against four pathogenic bacteria: Aeromonas hydrophila, Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio harveyi 2 . The results were striking:
The ethanolic extract demonstrated the strongest antibacterial activity, showing the highest bacterial inhibitory effects against V. parahaemolyticus and V. vulnificus 2 .
The minimum inhibitory concentrations (MICs) of the ethanolic extract were 10 mg/mL against A. hydrophila and V. harveyi, and 2.5 mg/mL against V. parahaemolyticus and V. vulnificus 2 .
Notably, the ethanolic extract was particularly effective against V. parahaemolyticus, a bacterium that causes acute hepatopancreatic necrosis disease in shrimps and gastrointestinal illness in humans 2 .
| Extract/Control | A. hydrophila | V. parahaemolyticus | V. vulnificus | V. harveyi |
|---|---|---|---|---|
| Aqueous extract | No inhibition | No inhibition | No inhibition | No inhibition |
| Acetone extract | No inhibition | 12.3 ± 0.6 | 11.0 ± 1.0 | No inhibition |
| Ethanol extract | No inhibition | 14.7 ± 0.6 | 12.7 ± 0.6 | No inhibition |
| 10% DMSO (control) | No inhibition | No inhibition | No inhibition | No inhibition |
| Oxytetracycline (100 µg/mL) | 22.7 ± 0.6 | 20.0 ± 0.0 | 25.3 ± 0.6 | 25.0 ± 0.0 |
This research suggests that N. pubescens extract could potentially be used as a natural antibiotic agent to treat bacterial infections in fish and aquatic animals, offering an environmentally friendly alternative to synthetic antibiotics that contributes to antimicrobial resistance 2 .
Beyond cardiovascular and antimicrobial applications, research has uncovered several other medicinal properties of Nymphaea pubescens:
The flower extract has demonstrated significant anti-inflammatory activity and protective effects against chemically-induced hepatotoxicity (liver damage) in rats 6 . The aqueous extract of the flower showed strong free radical scavenging activity, which likely contributes to these protective effects.
Traditional systems of medicine have employed N. pubescens for treating diabetes, inflammation, liver disorders, urinary disorders, and as a bitter tonic 3 9 . The seeds are cooked and believed to be beneficial for diabetic patients, while the flowers have been used as a blood purifier and for treating jaundice and eye disorders 6 .
The tuber of water lily has been identified as a good source of nutrients and natural antioxidants. Analysis shows it contains approximately 67.7% carbohydrates, 8.57% protein, and 9.78% fiber, making it a potential dietary supplement to meet nutritional requirements 9 .
67.7%
8.57%
9.78%
Studying the therapeutic potential of Nymphaea pubescens requires specific laboratory techniques and reagents. Here are some essential tools from the researcher's toolkit:
Serves as an effective solvent for extracting phytochemicals, particularly flavonoids, alkaloids, phenolic acids, and tannins 2 .
Used to identify and quantify specific phenolic and flavonoid compounds in the extracts, such as gallic acid, catechin, and rutin 2 .
Essential for measuring vasorelaxant effects on isolated blood vessels by recording isometric force changes 5 .
A nitric oxide synthase inhibitor used to investigate the role of the NO pathway in vasorelaxation 5 .
Determines the lowest concentration of an extract required to inhibit bacterial growth 2 .
A common method for evaluating the free radical scavenging activity and antioxidant capacity of plant extracts 6 .
The journey of exploring Nymphaea pubescens exemplifies how traditional knowledge and modern science can converge to uncover nature's hidden treasures. From its beautiful presence in aquatic landscapes to its complex chemical architecture, this remarkable plant continues to reveal therapeutic secrets that may address pressing health challenges.
As research advances, we may see N. pubescens derivatives developed into novel cardiovascular treatments, natural antimicrobial agents for aquaculture, or potent anti-inflammatory formulations. However, responsible management of this species is crucial, given its invasive potential in some ecosystems.
The hairy water lily stands as a powerful reminder that solutions to complex problems may sometimes be found floating quietly in nature, waiting for curious minds to discover their hidden depths.